Fatigue And Durability Analysis Of Rack-and-Pinion Gear Mechanism

For aircraft mechanical mechanisms,not only do they have to meet the maximum stress design,but they also have more definite requirements for fatigue life.The design of fatigue durability life has become an important consideration for aircraft mechanical structures.In order to evaluate the fatigue durability life of aircraft structure by theoretical calculation,a modern fatigue durability engineering method-a small amount of fatigue simulation technology combined with a large amount of test data-is used to analyze the fatigue durability life of the rack and pinion mechanism of a type of aircraft seam wing.The details are as follows:(1)The theoretical basis and general analysis methods of fatigue durability life are introduced by analyzing the stresses and stress changes during motion of the seam-wing gear rack.The modern fatigue durability engineering integration method is adopted for the seam-wing gear rack mechanism,which is conducive to evaluating the fatigue durability life of the seam-wing gear rack because it contains both the reliability of the experimental method and the flexibility and feasibility of finite elements for improvement.(2)Simulation analysis of a model seam-wing gear rack mechanism,modeling of the seamwing gear rack mechanism,static and dynamic finite element analysis of the seam-wing gear rack,and fatigue durability life analysis.The relationship between the ultimate torque and maximum stress of the applied gear and the fatigue life is analyzed for the static fatigue life;the effect of dynamic friction coefficient and gear speed on the fatigue durability life is analyzed for the kinetic fatigue life.(3)Fatigue durability test of aircraft seam gear rack was conducted,and fatigue durability strain data was obtained through test scheme design,test hardware(strain gauge and strain tester MX1615),and test software(CATMAN)data acquisition;fatigue durability strain data was obtained through three modules of test data analysis and processing: image data editing,detection and removal of burrs,and conversion of strain data into stress data to obtain fatigue life analysis stress data;fatigue durability life analysis was performed on the test analysis and processed stress data to study the factors affecting fatigue durability life,and further the maximum torque applied to the gear was obtained through the inverse life method.By studying the fatigue durability life of the seam-wing gear rack mechanism as described above,it can be concluded that the static and dynamic fatigue life simulations meet the design requirements,the design requirements for bending fatigue strength and contact fatigue strength of the teeth of the seam-wing gear rack mechanism are satisfied.The fatigue life analysis of the four sets of test data processed by the analysis shows that the slit-wing gear rack meets the design life requirements;further study the factors affecting the fatigue durability life: dynamic friction coefficient,surface roughness,gear speed,applied load,and surface treatment method.The feasibility of the modeling simulation analysis and the study of the factors affecting fatigue life is also verified,which provides a theoretical basis for the processing design of the slit-wing gear rack.